To make weapons, armor, jewelry or tailor...you need to find the npcs that are like grocer people, but they hold items for weapons. They are sometimes near the blacksmith and are named something relatively easy to find like "jeweler mary" or something similar.
Once you find these people, there should be one of them that gives instructions and teaches you how to make your first item. To make something, you need the crafting tool, which can be bought from one of the npcs (non playing characters), a metal also bought from an npc, and then you can find gems from xp or buy them from the npc (the bought ones are common like "glass" for example) and use them in the mix.
Not too sure about the different combinations you can use, for each combination just takes trying different things...and sometimes you will make something...and sometimes nothing. But you go under your tradeskills in the start menu and it will show you to experiment or use a receipe.
You will need to experiment to figure out a receipe first and then once you figure one out , you can use that receipe over and over again. Once you have created an item, that will give you xp points towards your crafting level. I think, not too sure I didnt go far with my crafting, that there are only 10 levels to each craft. Each level allows you to craft up to a certain level of items. Example level 1 may allow you to craft up to level 8 weapons. (dont remember if thats true..but you get the point).
Thats pretty much a shaky overview that hopefully helps out some. I hope you find the npc that explains how to craft better than I can...or ask around to someone and hopefully they dont mind helping a newbie (snicker) ...LOL had to add that...am just kidding. But I am sure there are plenty of people that dont mind explaining more if you have questions. Have a great day!